Host compound, organic electroluminescent material containing double hosts and organic electroluminescent device

Abstract

According to the host compound, the organic electroluminescent material containing double hosts and the organic electroluminescent device provided by the invention, the first host compound with a specific structure and the second host compound with a specific structure are compounded, and triazine and anthracene in the first host compound are matched; a donor-acceptor structure in a molecule is formed, HOMO and LUMO energy levels of the molecule can be effectively adjusted, two phenyl groups are introduced to an anthracene ring, steric hindrance can be increased, plane stacking can be prevented, the glass-transition temperature can be increased, the service life of a device can be prolonged, meanwhile, a second main body with triarylamine is matched, and the photoelectric conversion efficiency can be improved. By using the double-main-body material, triplet excitons can be dispersed on two main bodies, triplet-triplet annihilation (TTA) can be reduced, the driving voltage can be effectively reduced when the double-main-body material is applied to the organic electroluminescent device, meanwhile, the luminous efficiency of the device can be improved, and the service life of the device can be prolonged.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescent materials technology, specifically relating to a host compound, an organic electroluminescent material containing two hosts, and an organic electroluminescent device. Background Technology

[0002] OLED (Organic Light Emitting Display) refers to the phenomenon where organic semiconductor materials and light-emitting materials emit light through carrier injection and recombination under an electric field. The principle involves using an ITO transparent electrode and a metal electrode as the anode and cathode, respectively. Under a certain voltage, electrons and holes are injected from the cathode and anode into the electron and hole transport layers, respectively. These electrons and holes then migrate through the electron and hole transport layers to the light-emitting layer, where they meet, forming excitons and exciting the light-emitting molecules. These molecules then emit visible light through radiative relaxation. However, the organic light-emitting materials at the core of OLEDs are susceptible to oxidation and humidity, resulting in a significantly shorter lifespan compared to inorganic materials. Furthermore, the materials at each pixel also face challenges related to light decay. Therefore, further research is needed on OLEDs in terms of luminous efficiency and lifespan.

[0003] OLED devices mainly consist of the following components: an anode, a cathode, an organic semiconductor layer, and a charge transport layer. When a voltage is applied to an OLED device, electrons are injected from the cathode into the organic semiconductor layer, while holes are injected from the anode. These electrons and holes meet in the organic semiconductor layer and combine to form electron-hole pairs, or excitons. These excitons migrate within the organic semiconductor layer, and when they encounter a light-emitting center, they release photons, thus producing visible light. Since the radiative transitions of triplet excitons in most organic molecules are forbidden, their contribution to electroluminescence is small. However, by doping with organometallic complexes such as platinum, iridium, and osmium, triplet excitons from organic molecules can be transferred to the triplet state of the metal complex, thereby improving the efficiency of organic light-emitting devices. However, the most critical issues for achieving large-scale industrialization of organic electroluminescent devices are high device performance and long lifespan.

[0004] Therefore, how to provide a long-life, low-driving-voltage organic electroluminescent material and device with dual host structures is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a host compound, an organic electroluminescent material containing two hosts, and an organic electroluminescent device. The present invention disperses triplet excitons on two hosts by using a dual host material, thereby reducing triplet-triplet annihilation (TTA), which reduces the driving voltage of the organic electroluminescent device while improving the luminous efficiency and lifespan of the device.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a host compound having the structure shown in Formula I:

[0008]

[0009] Ar1 and Ar2 are each independently selected from hydrogen, substituted or unsubstituted C6 to C6. 42 Aryl, substituted or unsubstituted C3-C 30 Heteroaryl, substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, substituted or unsubstituted C 10 ~C 30 Any one of the fused ring groups;

[0010] L1, L2, and L3 are each independently selected from the connecting bond, substituted or unsubstituted C6-C. 30 aryl, substituted or unsubstituted C3-C 30 Any of the heteroaryl groups.

[0011] In one embodiment of the present invention, the compound with the structure shown in Formula I has the structures shown in Formulas I-a to I-d:

[0012]

[0013] In one embodiment of the present invention, Ar1 and Ar2 are each independently selected from hydrogen, substituted or unsubstituted C6-C. 18 Aryl, substituted or unsubstituted C3-C 24 Heteroaryl, substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl;

[0014] L1, L2, and L3 are each independently selected from the connecting bond, substituted or unsubstituted C6-C. 18 Alpha-aryl.

[0015] In one embodiment of the present invention, Ar1 and Ar2 are each independently selected from hydrogen, one of the following structures, or any combination thereof:

[0016]

[0017] L1, L2, and L3 are each independently selected from the linking bond, phenylene, and naphthylene; the dashed line indicates the linking site.

[0018] In one embodiment of the present invention, the heteroaryl group is a monocyclic aromatic group containing at least one heteroatom and / or a polycyclic aromatic cyclic group containing at least one heteroatom, wherein the heteroatom is one or more of O, S, N, and P.

[0019] In one embodiment of the present invention, the fused ring group includes a fused aromatic ring sharing at least two carbon atoms, and also includes two fused aromatic rings connected by a single bond.

[0020] In one embodiment of the present invention, "substitution" means that the hydrogen atom bonded to the carbon atom of the compound becomes another substituent, and there is no limitation on the position of substitution, as long as the position is where the hydrogen atom is substituted, that is, the position where the substituent can be substituted, and when two or more substituents are substituted, the two or more substituents can be the same as or different from each other.

[0021] In one embodiment of the present invention, the substituted group in "substituted or unsubstituted" is selected from deuterium, fluorine, cyano, phenyl, C1-C6. 10 Alkyl, deuterium-substituted C1-C 10 Alkyl, C3-C 10 cycloalkyl, C3-C 10 Heterocyclic alkyl, deuterated C3-C 10 Heterocyclic alkyl groups, wherein the heteroatoms are selected from oxygen, nitrogen, phosphorus, and sulfur;

[0022] In one embodiment of the present invention, the host compound of Formula I has the following structure, but is not limited thereto:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034] The above are some specific structural forms of the main compounds, but are not limited to these chemical structures. All compounds based on structural formula I, with simple transformations of groups within the defined range, should be included.

[0035] A second objective of this invention is to provide a dual-host organic electroluminescent material, comprising a first host material and a second host material, wherein the first host material is a host compound having the structure shown in Formula I, and the second host material has the structure shown in Formula II.

[0036]

[0037] R1, R2, and R3 are each independently selected from substituted or unsubstituted C6-C. 42 Aryl, substituted or unsubstituted C3-C 30 Any one of heteroaryl, substituted or unsubstituted silyl groups;

[0038] L4, L5, and L6 are selected from the linker, substituted, or unsubstituted C6-C. 18 Aryl.

[0039] In one embodiment of the present invention, R1, R2, and R3 are each independently selected from the following structures and any combination thereof:

[0040]

[0041] In one embodiment of the present invention, L4, L5, and L6 are selected from linkages, phenylene, and naphthylene; the dashed line represents the linkage site.

[0042] In the above technical solution, "substituted or unsubstituted" means that the group can be unsubstituted or substituted by one or more substituents. "Substitution" means that the hydrogen atom bonded to the carbon atom of the compound becomes another substituent. There is no restriction on the position of substitution, as long as the position is where the hydrogen atom is substituted, that is, the position where the substituent can be substituted. When two or more substituents are substituted, the two or more substituents can be the same as or different from each other.

[0043] In one embodiment of the present invention, the heteroaryl group comprises a monocyclic aromatic group and a polycyclic aromatic ring system with at least one heteroatom, wherein the heteroatom is one or more of O, S, N, and P.

[0044] In one embodiment of the present invention, the substituted group in "substituted or unsubstituted" is selected from deuterium, fluorine, phenyl, C1-C4. 10 Alkyl, deuterium-substituted C1-C 10 Alkyl, C3-C 10 cycloalkyl, C3-C 10 Heterocyclic alkyl, deuterated C3-C 10 Heterocyclic alkyl groups, wherein the heteroatoms are selected from oxygen, nitrogen, and sulfur.

[0045] In one embodiment of the present invention, the compound with the structure shown in Formula II is selected from any of the following, but is not limited thereto:

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] In one embodiment of the present invention, the mass ratio of the first main material to the second main material is 1:99-99:1; preferably 20:80-80:20; more preferably 30:70-70:30. The sum of the two is 100. Specific ratios can be 1:99, 5:95, 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 55:45, 60:40, 60:35, 70:30, 75:25, 80:20, 90:10, 95:5, 99:1.

[0056] The present invention also provides a method for preparing the above-mentioned organic electroluminescent material containing two main bodies, comprising the following steps:

[0057] 1) Preparation of intermediate compound M

[0058] The reaction route of intermediate compound M is as follows:

[0059]

[0060] Wherein: chlorine in reactant 1 can be replaced with other halogens, such as I and Br; borate groups in reactant 2 can be replaced with borate ester groups, such as the common pinacol borate ester.

[0061] X represents a halogen, such as Cl, Br, and I. Ar1, Ar2, L1, L2, and L3 are as defined above.

[0062] The specific preparation method of the intermediate compound M includes the following steps:

[0063] Under nitrogen protection, reactant 1 (1 eq), reactant 2 (1-1.2 eq), and potassium carbonate (3-4 eq) were weighed and added to the reaction system. Toluene, ethanol, water (V:V:V = 2:1:1) and catalyst tetrakis(triphenylphosphine)palladium (0.05-0.08 eq) were added. The mixture was refluxed at 90-110℃ for 20-24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25℃, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate M-1 of the compound shown.

[0064] Under nitrogen protection, intermediate M-1 (1 eq), reactant 3 (1-1.2 eq), and potassium carbonate (3-4 eq) were weighed and added to the reaction system. Toluene, ethanol, water (V:V:V = 2:1:1) and catalyst tetra(triphenylphosphine)palladium (0.05-0.08 eq) were added. The mixture was refluxed at 90-100℃ for 20-24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25℃, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate M-2 as shown.

[0065] Under nitrogen protection, intermediate M-2 (1 eq), reactant 4 (1-1.2 eq), and potassium carbonate (3-4 eq) were weighed and added to the reaction system. Toluene, ethanol, water (V:V:V = 2:1:1) and catalyst tetrakis(triphenylphosphine)palladium (0.05-0.08 eq) were added. The mixture was refluxed at 90-110℃ for 20-24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25℃, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate M as shown.

[0066] Synthesis of Compound Formula I:

[0067]

[0068] Under nitrogen protection, reactant 5 (1 eq), reactant 6-boronate pinacol ester (1-1.2 eq), potassium acetate (2.5-3 eq), tris(dibenzylacetone)dipalladium (0.01-0.03 eq), X-phos (0.08-0.24 eq), and 1,4-dioxane were added to a three-necked flask. The mixture was heated to 90-100℃ and refluxed for 20-24 hours. After the reaction was completed, purified water and dichloromethane were added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain the intermediate compound I-1 shown.

[0069] X-phos's chemical name is 2-bicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, and its CAS number is 564483-18-7.

[0070] Under nitrogen protection, intermediate M (1 eq), intermediate compound I-1 (1-1.2 eq), and potassium carbonate (3-4 eq) were weighed and added to the reaction system. Toluene, ethanol, water (V:V:V = 2:1:1) and catalyst tetrakis(triphenylphosphine)palladium (0.05-0.08 eq) were added. The mixture was refluxed at 90-110℃ for 20-24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25℃, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain compound I as shown.

[0071] In one embodiment of the present invention, the preparation method of compound formula II specifically includes the following steps:

[0072] The specific synthesis route is as follows:

[0073]

[0074] Specific preparation method of Formula II:

[0075] Reactant 7 (1-1.2 eq), reactant 8 (1 eq), and sodium tert-butoxide (2-3 eq) were weighed and added sequentially to a reaction vessel. Toluene was then added as a reaction solvent. Under nitrogen protection, catalysts Pd2(dba)3 (0.01-0.03 eq) and P(t-Bu)3 (0.02-0.06 eq) were added. The mixture was refluxed at 100-120°C for 20-24 hours under nitrogen protection. Then, it was cooled to 25°C, purified water was added, and the mixture was stirred for 30 minutes. After standing and separating the layers, the mixture was separated and subjected to column chromatography to obtain intermediate II-1.

[0076] Intermediate II-1 (1 eq), reactant 9 (1-1.2 eq), and sodium tert-butoxide (2-3 eq) were weighed and added sequentially to a reaction vessel. Toluene was then added as the reaction solvent. Under nitrogen protection, catalysts Pd2(dba)3 (0.01-0.03 eq) and P(t-Bu)3 (0.02-0.06 eq) were added. The mixture was refluxed at 100-120°C for 20-24 hours under nitrogen protection. Then, it was cooled to 25°C, purified water was added, and the mixture was stirred for 30 minutes. After standing and separating the layers, the mixture was separated and subjected to column chromatography to obtain compound II as shown.

[0077] This invention also claims protection for the use of the above-mentioned dual-host organic electroluminescent material in the preparation of organic electroluminescent devices.

[0078] The present invention also provides an organic electroluminescent device, the organic electroluminescent device comprising a first electrode, a second electrode, and an organic electroluminescent material layer disposed between the first electrode and the second electrode; and the organic electroluminescent material layer comprising a light-emitting layer; the light-emitting layer comprising a host material having the structure shown in Formula I and a dopant material; or the light-emitting layer comprising an organic electroluminescent material containing two hosts and a dopant material.

[0079] In one embodiment of the present invention, the mass ratio of the organic electroluminescent material containing two main bodies to the doped material is (1-99):(99-1). The sum of the two is 100. Specific ratios can be 1:99, 5:95, 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 55:45, 60:40, 60:35, 70:30, 75:25, 80:20, 90:10, 95:5, 96:4, 97:3, 98:2, or 99:1.

[0080] In one embodiment of the present invention, the organic electroluminescent device includes an anode, a hole transport region, an emissive layer, an electron transport region, and a cathode; the emissive layer includes a first host material having the structure shown in Formula I and a second host material having the structure shown in Formula II.

[0081] As an anode material, a material with a high work function is generally preferred to facilitate hole injection into the organic material layer. The anode materials that can be used for the first electrode of the organic electroluminescent device of the present invention include: metals, such as vanadium, chromium, copper, zinc, and gold, or alloys thereof; metal oxides, such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides, such as ZnO:Al or SnO2:Sb; conductive polymers, such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxo)thiophene] (PEDOT), polypyrrole, and polyaniline, but are not limited thereto.

[0082] As a cathode material, materials with a small work function are generally preferred to facilitate electron injection into the organic material layer. The cathode materials that can be used for the second electrode of the organic electroluminescent device of the present invention include: metals, such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; multilayer materials, such as LiF / Al or LiO2 / Al; and so on, but are not limited thereto.

[0083] The hole injection layer material is a material that receives holes from the anode at low voltage, and the highest occupied molecular orbital (HOMO) of the hole injection material is preferably between the work function of the anode material and the HOMO of the surrounding organic material layer. Hole injection materials include metalloporphyrins, oligothiophenes, arylamine-based organic materials, hexanitrile hexaazabenzophenanthrene-based organic materials, quinacridone-based organic materials, perylene-based organic materials, anthraquinones, and conductive polymers based on polyaniline and polythiophene, etc.

[0084] Hole transport layer materials are materials that can receive holes from the anode or hole injection layer and transport the holes to the light-emitting layer, and have high hole mobility; and hole transport layer materials include, but are not limited to, arylamine-based organic materials, conductive polymers, block copolymers having both conjugated and non-conjugated parts.

[0085] An electron blocking layer can be disposed between the hole transport layer and the light-emitting layer. Materials known in the art, such as arylamine-based organic materials, can be used as the electron blocking layer.

[0086] The main material of the light-emitting layer is selected from the structure of this invention.

[0087] The hole blocking layer can be disposed between the electron transport layer and the light-emitting layer, and can be made of materials known in the art, such as triazine-based compounds.

[0088] The electron transport layer facilitates electron transport. Electron transport materials are those that advantageously receive electrons from the cathode and transport them to the light-emitting layer, exhibiting high electron mobility. These include, but are not limited to, Al complexes of 8-hydroxyquinoline; complexes containing Alq3; organic free radical compounds; hydroxyflavonoid-metal complexes, etc. The thickness of the electron transport layer can range from 1 nm to 50 nm. Electron transport layers with a thickness of 1 nm or greater have the advantage of preventing a decrease in electron transport properties, while thicknesses of 50 nm or less have the advantage of preventing an increase in driving voltage caused by an excessively thick electron transport layer.

[0089] The electron injection layer can promote electron injection, and the electron injection material preferably has the ability to transport electrons, exhibiting an electron injection effect from the cathode, and demonstrating excellent electron injection effect on the light-emitting layer or light-emitting material. It prevents excitons generated in the light-emitting layer from migrating to the hole injection layer, and also possesses excellent thin film forming ability. Specific examples include fluorenones, anthraquinone dimethane, biphenylquinone, thiamethane dioxide, azoles, diazoles, triazoles, imidazoles, perylenetetracarboxylic acid, fluorenemethane, anthrones, and their derivatives, metal complexes, nitrogen-containing five-membered ring derivatives, etc., but are not limited to these.

[0090] Depending on the materials used, the above-mentioned organic electroluminescent devices can be top-emitting, bottom-emitting, or bilaterally emitting.

[0091] Furthermore, the organic electroluminescent device described in this invention can be used in organic solar cells, electronic paper, organic photoreceptors, or organic thin-film transistors.

[0092] The present invention has the following beneficial effects:

[0093] This invention employs a combination of a first host material compound with a specific structure and a second host material compound with a specific structure. The first host material contains triazine and anthracene, forming an intramolecular "donor-acceptor" structure that effectively modulates the HOMO and LUMO energy levels. Furthermore, the introduction of two phenyl groups onto the anthracene ring increases steric hindrance, prevents planar stacking, increases the glass transition temperature, and extends device lifespan. Simultaneously, the second host material compound, containing triarylamine, allows triplet excitons to be dispersed across the two hosts, reducing triplet-triplet annihilation (TTA). In addition, the first host material compound exhibits faster electron mobility, lower operating voltage, higher quantum efficiency, and longer lifespan. When both are used as the host of the luminescent layer, they reduce the driving voltage of the organic electroluminescent device while improving the device's luminous efficiency and lifespan. Attached Figure Description

[0094] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0095] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of compound R008. Detailed Implementation

[0096] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0097] Additionally, it should be noted that the values ​​given in the following embodiments are as accurate as possible; however, those skilled in the art will understand that due to unavoidable measurement errors and experimental issues, each number should be understood as an approximation rather than an absolutely accurate value.

[0098] Example 1

[0099] Preparation of compound R008

[0100]

[0101] Under nitrogen protection, raw material A (CAS:239255-14-3) (1 eq), raw material B (CAS:24388-23-6) (2.4 eq), potassium carbonate (3 eq), tetrakis(triphenylphosphine)palladium (0.03 eq), toluene, ethanol, and water were added to a three-necked flask. The mixture was heated to 100°C and refluxed for 24 hours. After the reaction was completed, purified water and dichloromethane were added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain the intermediate compound R008-1 (yield: 79.2%).

[0102]

[0103] Under nitrogen protection, intermediate compound R008-1 (1 eq), starting material C-borane pinacol ester (1.2 eq), potassium acetate (3 eq), tris(dibenzylacetone)dipalladium (0.03 eq), X-phos (0.24 eq), and 1,4-dioxane were added to a three-necked flask. The mixture was heated to 110 °C and refluxed for 24 hours. After the reaction was completed, purified water and dichloromethane were added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate compound R008-2 (yield: 84.3%).

[0104]

[0105] Under nitrogen protection, intermediate compound R008-2 (1 eq), starting material D (CAS: 2648-51-3) (1.2 eq), potassium carbonate (4 eq), tetrakis(triphenylphosphine)palladium (0.04 eq), toluene, ethanol, and water were added to a three-necked flask. The mixture was heated to 100°C and refluxed for 24 hours. After the reaction was completed, purified water and dichloromethane were added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate compound R008-3 (yield: 69.2%).

[0106]

[0107] Intermediate compound R008-3 (1 eq), (methoxymethyl)triphenylphosphine chloride (1.5 eq), and THF were added to a reaction vessel and stirred for 15 minutes. Potassium tert-butoxide solution was then slowly added dropwise at 5°C. The temperature was then slowly increased, and the mixture was stirred at room temperature for 5 hours. Distilled water was then added. After the reaction was complete, the organic layer was extracted with ethyl acetate, the organic phase was dried over sodium sulfate, the solvent was removed by a rotary evaporator, and the mixture was purified by column chromatography to give intermediate compound R008-4 (yield: 67.6%).

[0108] Intermediate compound R008-4 (1 eq), boron trifluoride ether (1.5 eq), and dichloromethane were added to a reaction vessel and stirred for 4 hours. After the reaction was complete, the organic layer was extracted with dichloromethane and water, dried with sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified by column chromatography to give intermediate compound R008-5 (yield: 69.5%).

[0109]

[0110] Under nitrogen protection, intermediate compound R008-5 (1 eq), starting material C-borane pinacol ester (1.2 eq), potassium acetate (3 eq), tris(dibenzylacetone)dipalladium (0.01 eq), X-phos (0.08 eq), and 1,4-dioxane were added to a three-necked flask. The mixture was heated to 90 °C and refluxed for 24 hours. After the reaction was completed, purified water and dichloromethane were added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate compound R008-6 (yield: 77.4%).

[0111]

[0112] Under nitrogen protection, intermediate compound R008-6 (1 eq), raw material E (CAS: 21902-34-1) (1.2 eq), potassium acetate (3 eq), tris(dibenzylacetone)dipalladium (0.03 eq), X-phos (0.24 eq), and 1,4-dioxane were added to a three-necked flask. The mixture was heated to 110 °C and refluxed for 24 hours. After the reaction was completed, purified water and dichloromethane were added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain R008.

[0113] Test value: 589.85; Yield: 73.7%; HPLC > 99%; Elemental analysis: C, 87.43; H, 5.42; N, 7.25.

[0114] Example 2

[0115] Preparation of compound H28

[0116]

[0117] Weigh N-([1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]-3-amine (1 eq), 10-chloro-2-phenylphenanthrene[3,4-d]oxazole (1 eq), and sodium tert-butoxide (2 eq) into a reaction flask. Add toluene, and under nitrogen protection, add catalysts Pd2(dba)3 (0.01 eq) and P(t-Bu)3 (0.02 eq). Reflux at 120 °C for 24 hours under nitrogen protection, then cool to 25 °C. Add 200 mL of purified water, stir for 30 minutes, allow to stand for layering, separate the layers, and perform column chromatography to obtain product H28.

[0118] Test value: 614.86; Yield: 77.0%; HPLC > 99%; Elemental analysis: C, 87.62; H, 5.11; N, 4.65; O, 2.72.

[0119] It should be noted that other compounds of the present invention can be obtained by referring to the synthesis methods of Examples 1 and 2 listed above, so they will not be described in detail here.

[0120] Device Example 1

[0121] Organic electroluminescent devices were prepared using compound R008 prepared in Example 1 and compound H28 prepared in Example 2.

[0122] Specifically, the fabrication method of organic electroluminescent devices is as follows:

[0123] ITO anode: The ITO (indium tin oxide) glass substrate with a coating thickness of 1500 angstroms was cleaned twice with distilled water and ultrasonically washed for 30 min. Then it was cleaned twice with distilled water and ultrasonically washed for 10 min. After washing, it was ultrasonically washed sequentially with methanol, acetone and isopropanol (5 min each time). After drying, it was transferred to a plasma cleaner and washed for 5 min to obtain the ITO anode.

[0124] HIL (Hole Injection Layer): In a vapor deposition machine, 200 Å of 4,4',4”-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA) is vacuum-deposited onto an ITO anode to form a hole injection layer.

[0125] HTL (Hole Transport Layer): A hole transport layer is formed by vacuum evaporating NPB (i.e., N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine) at 400 Å onto the hole injection layer.

[0126] Emitting layer: The emitting layer includes a first host material, a second host material and a guest dopant. After forming a hole injection layer and a hole transport layer, the emitting layer is formed on the HTL: The first host compound and the second host compound are introduced as hosts into two chambers of the vacuum vapor deposition apparatus, and compound Z1 is introduced as a dopant into another chamber.

[0127] The first host material and the second host material are evaporated at a rate of 1:1, and the dopant material is evaporated simultaneously at different rates, and a doping amount of 3 wt% based on the total amount of host and dopant is deposited to form a light-emitting layer with a thickness of 40 nm on the second hole transport layer.

[0128] HBL (Hole Blocking Layer): A hole blocking layer is formed by vacuum evaporating 100 Å of bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq) onto the luminescent layer.

[0129] ETL (Electron Transport Layer): 400 Å of 8-hydroxyquinoline aluminum (Alq3) is vacuum-deposited onto the hole blocking layer to form the electron transport layer.

[0130] EIL (Electron Injection Layer): LiF2 10 angstroms is vacuum-deposited on the electron transport layer to form the electron injection layer.

[0131] Cathode: An organic electroluminescent device is obtained by evaporating 1500 angstroms of Al onto the electron injection layer to form a cathode.

[0132] Referring to the organic electroluminescent devices and their preparation methods provided in Examples 1 and 2, another 60 organic electroluminescent compounds were selected to replace the main materials in Examples 1 and 2 for vapor deposition, and organic electroluminescent devices of the corresponding compounds were prepared.

[0133] Red-light doped material (Z1):

[0134]

[0135] Performance testing

[0136] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Comparative Examples 1-18 and Device Examples 1-32 were characterized at a brightness of 5000 nits. The test results are shown in Table 1 below.

[0137] The comparative example structure is as follows:

[0138]

[0139] Table 1

[0140]

[0141]

[0142]

[0143] As can be seen from Table 1, the organic electroluminescent devices of Device Examples 1-2 of the present invention have significantly better performance than those of Comparative Examples 1-12. The devices prepared by the present invention have lower driving voltage, higher luminous efficiency, and longer lifetime. Furthermore, the device performance of Device Examples 3-32 is significantly improved compared to that of Comparative Examples 13-18.

[0144] In the organic electroluminescent compound provided in this invention, the anthracene ring acts as a blue chromophore and electron donor, and is paired with a triazine group as a strong electron acceptor, thereby achieving energy level regulation, inducing the TADF effect, providing electron transport capability, and enhancing thermal stability, thus improving the service life of the material; the two phenyl groups mainly act as steric hindrance groups, suppressing concentration quenching and ensuring high efficiency in solid state.

[0145] In summary, compared with organic electroluminescent devices prepared using comparative compounds E-1 to E-6 as the dual host materials for the light-emitting layer, the organic electroluminescent device prepared by the present invention has a lower band gap, which reduces the driving voltage; it also suppresses structural accumulation and improves service life.

[0146] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A host compound, characterized in that, The host compound has the compound structure shown in Formula I: in, Ar1 and Ar2 are each independently selected from any one of hydrogen, substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C3-C30 heteroaryl, substituted or unsubstituted phosphoxy, substituted or unsubstituted silyl, and substituted or unsubstituted C10-C30 fused cyclic groups; L1, L2, and L3 are each independently linked by any one of the following: substituted or unsubstituted C6-C30 arylene groups, or substituted or unsubstituted C3-C30 heteroarylene groups.

2. The main compound according to claim 1, characterized in that, The compound shown in Formula I has the structures of Formula I-a to I-d:

3. The host compound according to claim 1, characterized in that, Ar1 and Ar2 are each independently selected from hydrogen, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C3-C24 heteroaryl, substituted or unsubstituted phosphoxy, or substituted or unsubstituted silyl. L1, L2, and L3 are each independently linked by substituted or unsubstituted C6-C18 aryl groups.

4. The host compound according to claim 1, characterized in that, Ar1 and Ar2 are each independently selected from hydrogen, the following structures, and any combination thereof: L1, L2, and L3 are each independently linked to the phenylene group and the naphthylene group; Dashed lines indicate connection points.

5. The host compound according to claim 1, characterized in that, The heteroaryl group is a monocyclic aromatic group containing at least one heteroatom and / or a polycyclic aromatic ring group containing at least one heteroatom, wherein the heteroatom is one or more of O, S, N, and P; The fused ring group includes fused aromatic rings sharing at least two carbon atoms, and also includes two fused aromatic rings linked by a single bond; The term "substitution" refers to the replacement of a hydrogen atom bonded to a carbon atom of a compound with another substituent. There are no restrictions on the position of substitution, as long as the position is where the hydrogen atom is replaced. That is, the position that the substituent can replace. When two or more substituents are substituted, the two or more substituents can be the same as or different from each other. The substituted group in "substituted or unsubstituted" is selected from deuterium, fluorine, cyano, phenyl, C1-C10 alkyl, deuterated C1-C10 alkyl, C3-C10 cycloalkyl, C3-C10 heterocyclic alkyl, and deuterated C3-C10 heterocyclic alkyl, and its heteroatom is selected from oxygen, nitrogen, phosphorus, and sulfur.

6. The host compound according to claim 1, characterized in that, The host compound is selected from any one of the compounds shown in formulas R001 to R380:

7. An organic electroluminescent material containing two host materials, characterized in that, The organic electroluminescent material comprises a first host compound and a second host compound, wherein the first host compound is the host compound according to any one of claims 1-6; and the second host compound has the structure shown in Formula II: R1, R2, and R3 are each independently selected from any one of substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C3-C30 heteroaryl, or substituted or unsubstituted silyl groups; L4, L5, and L6 are selected from the linking bonds, substituted or unsubstituted C6-C18 aryl groups.

8. The organic electroluminescent material according to claim 7, characterized in that, R1, R2, and R3 are independently selected from the following structures and any combination thereof: L4, L5, and L6 are selected from linking bonds, phenylene, and naphthylene; Dashed lines indicate connection points.

9. The organic electroluminescent material according to claim 7, characterized in that, The second host compound is any one of the compounds shown in formulas H1 to H308:

10. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode. The organic layer includes a light-emitting layer, which includes the organic electroluminescent material with dual host as described in any one of claims 7-9. The organic layer further includes any one or a combination of at least two of the following: a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

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